Lock Ubuntu 10.04 screen while away

In windows i was used to this shortcut which locked my screen while i was away, by pressing WIN+L. In this way i was asurred that having a password, nobody would work on my computer.In ubuntu i found out that this shortcut does not exist, but there are others keyboard combination keys to lock the screen.

CTRL+ALT+L

Press them all at once.By default this will enable your screensaver which is blankscreen if you didn't configured the screensaver. To configure it, go to: SYSTEM -> PREFERENCES -> SCREENSAVER.